This invention relates to apparatus for storing and supplying water for use in a unit of catering equipment, such as a dishwasher.
In such equipment, a storage tank is often provided to hold a quantity of water supplied from a mains source so that, when the catering equipment requires water, this is supplied from the storage tank rather than directly from the mains source. In order reliably to supply the required amount of water, the storage tank has heretofore been designed to contain substantially more water than is required by the catering equipment at any time; this has meant that such storage tanks are large and either they must be mounted outside the housing of the unit or the size of the housing has to be increased in order that the storage tank may fit within the housing. In either case this leads to an increase in the overall size of the unit.
Furthermore, the storage tank is often used to contain hot water, and to keep the water at the correct temperature the tank must be insulated and/or means provided to heat the water so as to maintain it at the correct temperature. The larger the storage tank, therefore, the greater the amount of insulation material required and the more energy consumed in order to maintain the water within the storage tank at the correct temperature.
A desirable requirement of such storage tanks is that, in the event of a sudden drop in pressure in the mains water supply feeding the water storage tank, water from the storage tank is prevented from being drawn back into the mains supply, potentially contaminating the mains water supply with dirty water from the storage tank.